From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>, Daniel Kiper <daniel.kiper@oracle.com>
Cc: bhavesh.davda@oracle.com,
Eric DeVolder <eric.devolder@oracle.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH v2 2/2] kexec: remove spinlock now that all KEXEC hypercall ops are protected at the top-level
Date: Wed, 19 Apr 2017 12:52:52 +0100 [thread overview]
Message-ID: <e1870852-40b1-04af-404b-ab96b0b6491f@citrix.com> (raw)
In-Reply-To: <58F764320200007800151E62@prv-mh.provo.novell.com>
On 19/04/17 12:20, Jan Beulich wrote:
>>>> On 19.04.17 at 12:56, <daniel.kiper@oracle.com> wrote:
>> On Tue, Apr 18, 2017 at 04:49:48AM -0600, Jan Beulich wrote:
>>>>>> On 17.04.17 at 21:09, <eric.devolder@oracle.com> wrote:
>>>> The spinlock in kexec_swap_images() was removed as
>>>> this function is only reachable on the kexec hypercall, which is
>>>> now protected at the top-level in do_kexec_op_internal(),
>>>> thus the local spinlock is no longer necessary.
>>> But perhaps leave an ASSERT() there, making sure the in-hypercall
>>> flag is set?
>> I am not sure why but if at all I think that we should also consider
>> other key kexec functions then. Or put ASSERT() into do_kexec_op_internal()
>> just before "switch ( op )".
> The point of my placement suggestion was that the ASSERT()
> effectively replaces the lock acquire - the places you name
> didn't previously require any synchronization.
I'd recommend adding the ASSERT(), just to be on the safe side.
~Andrew
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next prev parent reply other threads:[~2017-04-19 11:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-17 19:09 [PATCH v2 0/2] kexec: Use hypercall_create_continuation to protect KEXEC ops Eric DeVolder
2017-04-17 19:09 ` [PATCH v2 1/2] kexec: use " Eric DeVolder
2017-04-18 10:48 ` Jan Beulich
2017-04-19 11:00 ` Daniel Kiper
2017-04-19 11:48 ` Andrew Cooper
2017-04-19 12:16 ` Daniel Kiper
2017-04-19 15:48 ` Eric DeVolder
2017-04-17 19:09 ` [PATCH v2 2/2] kexec: remove spinlock now that all KEXEC hypercall ops are protected at the top-level Eric DeVolder
2017-04-18 10:49 ` Jan Beulich
2017-04-19 10:56 ` Daniel Kiper
2017-04-19 11:20 ` Jan Beulich
2017-04-19 11:52 ` Andrew Cooper [this message]
2017-04-19 12:13 ` Daniel Kiper
2017-04-19 13:37 ` Jan Beulich
2017-04-19 15:49 ` Eric DeVolder
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